Self-locking spade terminal

ABSTRACT

The improved terminal has a wire barrel for mechanical deformation about a conductor placed therein and a locking spade blade at its opposite end. Locking is achieved about a terminal screw by inwardly extending nibs at the tine ends which restrict the blade slot and by the thickness of the tines which permits nesting within the thread of such screw. The resiliency of the terminal permits deflection of the tine nibs during installation.

United States Patent [72] Inventor Ilarle H. Lentils Bellevllle, NJ.[211 App]. No. 704,616 [22] Filed Feb. 12, 1968 [45] Patented June 29,1971 [73] Assignee The Thomas & Belts Co.

Eliabeth,N.J.

[S4] SELF-LOCKING SPADETERMINAL 2 Claims, 6 Drawing Figs.

52 0.5. CI 339/257, 339/277 [51] Int. 110" 11/22 [50] Field olSearch339/223, 252. 257.263, 256,258,277; 24/130;8S/8.8. 51; 287/135 [56]References Cited UNITED STATES PATENTS 783,061 2/1905 Mills 339/2571,214,470 1/1917 Jeffery 339/257 1,220,715 3/1917 Beck 339/223 1,633,9746/1927 Breisch.... 339/258 (C) 1,703,325 2/1929 Smarr 339/257 1,873,2708/1932 Blazer 24/108 2,157,007 5/1939 Offner..... 339/223 2,410,32110/1946 Matts 339/213 (T) 2,681,440 6/1954 Swengel 339/223 PrimaryExaminer-Marvin A. Champion Assistant Examiner-Joseph H. McGlynnArrorney-David Teschner PATENTEUJUNZSIQTI 3590.387

INVENTOR EARLE HL AND/5 ATTORNEY SELF-LOCKING SPADE TERMINALCROSS-REFERENCE TO RELATED APPLICATION This application is related tocopending Design Application D4800, filed on Nov. 23, I966. by EarleLandis for Spade Terminal Connector, assigned to the Assignee of theinstant invention, now abandoned BACKGROUND OF THE INVENTION l. Field ofthe Invention The invention is directed to the field of electricalconnectors of the solderless type. It finds utility in the connecting ofelectrical conductors to terminal blocks or the like. Terminal blocks aspresently used in the electronics field are made from phenolic or otherplastic materials and have therein at repetitive intervals a pluralityofelectrical terminal screws. Conductors must be fastened to thesescrews in such a manner that they may be easily installed or removedtherefrom. Common practice is to provide spade terminals which arefastened to the conductors to permit them to be readily applied to theterminal screws which are tightened upon the tines of the spade terminalto retain them in contact with the terminal block.

2. Description ofthe Prior Art Prior art spade terminals were fabricatedwith tines having parallel edges defining both the outer surface as wellas the terminal screw receiving slot. These terminals had tines whichwere tapered at their leading edge to permit easy insertion of the linesunder the terminal screw. Due to their construction, and the materialsfrom which they were generally fabricated, it was necessary that thetines be of sufficiently great width to prevent the spreading of thetines upon the tightening of the terminal screw. In addition, the tineswere of great thickness, again to prevent the tines from being deflectedoutwardly upon the tightening of the terminal screw. The spreading ofthe tines, in prior an spade terminals, caused a great deal ofdifficulty with respect to possible contact with adjacent terminals. Inan effort to solve this problem terminal blocks were constructed withplastic, or other insulating spacers, between respective terminalscrews. Such a practice was both expensive and greatly consumed themounting space available and thus decreased the termination densitywhich could be achieved by such devices. When such spade terminals wereused in situations subject to vibration. the loosening of the terminalscrew itself would permit the spade lug to separate from the terminalscrew and possibly short against additional cnnections or produce anundesired grounding of the circuit. In an effort to prevent the unwantedseparation of the spade terminal and the terminal screw some of theprior art spade ter' minals had upturned ends whose ends were turned ata 90 position or perpendicular to the normal plane of the main portionof the tines. Such upturning to some degree prevented the removal of thespade terminal from the terminal screw should the terminal screw becomeloosened, However, such an arrangement was not always satisfactorybecause the upturning of the tine ends reduced the possibility ofstacking and required that greater spacing be provided between adjacentlayers of terminal connections than would be required with a generallyflat spade terminal tine. In addition, the thickness of prior art spadeterminals prevented a tight fit from being achieved because it hinderedthe degree to which the terminal screw might be tightened.

SUMMARY OF THE INVENTION The present invention overcomes thedifficulties noted above with prior art spade terminals. The presentinvention provides a spade terminal which is self-locking in itsapplication and which is small in size and prevents unwanted tinespreading and at the same time is small enough to provide proper nestingbetween respective screw thread crests thus preventing interference withthe operation of the terminal screw. The spade terminal is formed from amaterial which is both highly conductive and highly resilient and thetint thereof are formed to gently taper inwardly and to terminal atinwardly facing nibs. As a result ofthe inward sloping of tlt tines andthe inwardly facing nibs the entrance to the termini screw-receivingslot is made smaller than the diameter of th screw itself. Thus a snapaction is achieved as the tine ends, c inturned nibs, are forced by theterminal screw. As the spad terminal is advanced to position theterminal screw at the en of the terminal screw-receiving slot, minimumclearance fo the terminal screw is provided by permitting the ends of thlines to return to their initial position in a somewhat closerelationship to one another thus preventing the unwante removal ofthespade terminal from the terminal screw. Due It the original forming ofthe spade terminal, and the manner it which it cooperates with theterminal screw, the tightening o the screw terminal does not cause thespreading of the tine and therefore a good mechanical, as well aselectrical connec tion, is achieved. Further, the thickness of the tinesis such a to be able to nest between the adjacent thread crests of thtterminal screw and thus minimize interference between lIlt spadeterminal and to position terminal screw and permit the greatest amountof tightening to be applied to the spade terminal. It is therefore anobject of this invention to provide as improved spade terminal which isself-locking.

It is still another object of this invention to provide an im provedform of spade terminal having inturned end nibs to prevent the unwantedremoval of the spade terminal from a terminal screw.

It is yet another object of this invention to provide an improved spadeterminal having both inturned tines and inturned tine nibs to preventunwanted removal of the spade terminal from a terminal screw.

It is yet another object of this invention to provide an improved spadeterminal ofsmall dimension to permit increasing the density ofconnections possible on a standard terminal board.

It is still another object of this invention to provide an improvedspade terminal with a minumum of interference between the spade terminaland the terminal screw to which it is mounted.

It is yet another object of this invention to provide an improved spadeterminal which is force fed and force removed from contact with theterminal screw of an electrical terminal block.

Other objects and features of the invention will be pointed out in thefollowing description and claims and illustrated in the accompanyingdrawings, which disclose, by way of example, the principle of theinvention and the best modes which have been contemplated for carryingthem out.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a prospective view showing aspade terminal con structed in accordance with the concepts of theinvention.

FIG. 2 is a top plan view of the spade terminal of FIG. 1.

FIG. 3 is a side view ofthe terminal of FIG. 1.

FIG. 4 is a top plan view ofa further embodiment ofa spade terminalconstructed in accordance with the concepts of the invention.

FIG. 5 is a top plan view of terminals constructed in accordance withthe concepts of this invention connected to an electrical tenninalblock.

FIG. 6 is a side view, in section, of the terminal block and terminalsof FIG. 5 taken along the lines 6-6.

Similar elements are given similar reference characters in each of therespective figures.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to FIGS. 1, 2 and 3a first embodiment of a spade terminal 10 constructed in accordance withthe concepts of the invention is shown. Spade terminal It] has a tubularportion 12 having an aperture 14 therein arranged to receive thestripped portion of an electrical conductor (not shown). that is. theportion of an electrical conductor whose insulation has been removed.The tubular portion l2 may be crimped about the portion of theelectrical conductor having its insulation removed by mechanical meansor may be soldered thereto. Extending from the tubular portion i2 is anarrow neck portion 16 which leads into the planar portion 18. Theplanar portion consists oi'the tines 20, which define a terminal screwreceiving slot 22. The tines 20 have a generally parallel portion 24 andan inclined portion 26. As can be seen. the edges bounding the terminalscrew-receiving slot 22 are generally parallel with the portion 24 ofthe tines 20. Each of the tines 20 terminates in an inwardly extendingnib 28.

The spacing between the most inwardly reaching portion of the nibs 28 issuch that it is smaller than the remainder ofthe terminalscrew-receiving slot 22. With this spade terminal slipped over aterminal screw. a snap action will be achieved wherein the nibs 26 andthe tines 20 are forced to expand to allow entrance of the terminalscrew not shown) into the terminal screw-receiving slot 22. Once theterminal screw has progressed beyond the nibs 28 the tines 20 areallowed to return to their initial position permitting the nibs 28 toblock the entrance of the terminal screw-receiving slot 22 and thusprevent the unwanted removal of the spade terminal from the terminalscrew. As will be described later with respect to FIG. 6 the thicknessof the tines is such that they will nest between the adjacent crests ofthe terminal screw to permit maximum closure oi the tines 20 and thusprovide the best grasping by the spade terminal l0 olthe terminal screw.

Although the tubular portiop i2 is shown throughout the figures inuninsulated form. it should be readily appreciated that an insulatedjacket may be provided atop the tubular portion 12 ildeslred.

Turning now to FIG. 4. there is shown a further form of the spadeterminal 36: constructed in accordance with the concepts oltheinvention. Spade terminal has a tubular portion 12 and from there a neckportion 16 leading to the planar portion 38. The planar portion 38 hastwo tines 40 which define terminal screw-receiving slot 42. The tines40. their outer edges 44 and inner edges 46 oi tines 40. are generallyparallel with one another and are generally inclined inwardly towards meanother so that the entry to the terminal screw-receiving lot 43 issmaller than anywhere else along its length. Each of he tines 40terminates in an lnturned nib 48. Nlbs 48 as is true i nibs 28 ofFIGS. 1. 1 and 3. further reduce the width of the ntrance to theterminal screw-receiving slot 42 and that perill a snap action to beachieved as the spade terminal 30 is rrced upon a terrnlnal screw (notshown). Additionally. the ight Inward tilt of the tines 40 also preventsthe unwanted treading of the tines during tightening of the terminalscrew I which the spade terminal 30 is attached.

To also decrease the ability of the terminal tines to spread iringtightening of the terminal screw the spade terminal is brlcsted frommaterial having a high yield tensile strength as :ll as highconductivity and is described in U.S. Pat. No.

Turning now to FIGS. 5 and 6 the relationship of the .citness of thespade terminals with respect to a terminal screw can better beappreciated. in FIG 5 there is shown a typical installation of two spadeterminals 60 and 64 to a terminal board 58. The first spade terminal 60is held to the terminal board 88 by means of a terminal screw 62 whilethe second spade terminal 64 is held to the terminal board 58 by meansof a second terminal screw 66. The relationship between the terminalscrew 66 and the tines 68 of the spade terminal 64 may better beappreciated from a viewing oi FIG. 6. As can be seen. the terminal screw66 is in a partially tightened condition and the spade terminal 64 hasbeen positioned so that the tines 68 extend about the terminal screw 66.The thickness of the tines 68 is so chosen that their thickness permitsthe nesting of the tines 68 between adjacent thread crests of terminalscrew 66 and thus permits maximum grasping between the spade terminal 64and the terminal screw 66.

in addition. this type of mounting minimizes the size requirementfor-the spade terminal an thus increases the packing density possible.

While there have been shown and described and pointed out thefundamental novel features of the invention as applied to the preferredembodiments. it will be understood that various omissions andsubstitutions and changes of the form and details of the devicesillustrated and in their operation may be made by those skilled in theart. without departing from the spirit of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

I claim:

l. A self-locking spade terminal fabricated from a resilient, highlyconductive alloy comprising: a tubular portion adapted to receive aportion of an electrical conductor from which the insulation has beenremoved; a planar portion; a solid, continuous. planar transitionportion extending in the same plane as said planar portion connected ata first end to said tubular portion and at a second end. opposite saidfirst end. to said planar portion; said planar portion comprising twotines separated by a terminal screw-receiving slot; two nibs, one foreach of said tines, each coupled to its associated tine adjacent thefree ends thereof and partially blocking said terminal screw-receivingslot each oi said nibs having a chamfered edge adjacent the couplingbetween said nib and its associated tine and the free end of said tine;said tines being proportioned to flex outwardly with respect to oneanother when the chemlered edges of said nibs are brought into contactwith a terminal screw normal to the plane of said terminal and to returninwardly to their initial position when said terminal is removed fromcontact with said terminal screw whereby the engagement oi'the chamferededges of said nibs with a terminal screw causes the outward deflectionof said tines only until the terminal is advanced to place the terminalscrew within the terminal screw-receiving slot permitting the tines onlyto return to their initial position and barring removal of the terminalfrom the terminal screw by the position of the nibs in the path of theterminal screw.

2. A terminal as defined in claim i having an insulation jacket placedabout said tubular portion.

1. A self-locking spade terminal fabricated from a resilient, highlyconductive alloy comprising: a tubular portion adapted to receive aportion of an electrical conductor from which the insulation has beenremoved; a planar portion; a solid, continuous, planar transitionportion extending in the same plane as said planar portion connected ata first end to said tubular portion and at a second end, opposite saidfirst end, to said planar portion; said planar portion comprising twotines separated by a terminal screw-receiving slot; two nibs, one foreach of said tines, each coupled to its associated tine adjacent thefree ends thereof and partially blocking said terminal screwreceivingslot each of said nibs having a chamfered edge adjacent the couplingbetween said nib and its associated tine and the free end of said tine;said tines being proportioned to flex outwardly with respect to oneanother when the chamfered edges of said nibs are brought into contactwith a terminal screw normal to the plane of said terminal and to returninwardly to their initial position when said terminal is removed fromcontact with said terminal screw whereby the engagement of the chamferededges of said nibs with a terminal screw causes the outward deflectionof said tines only until the terminal is advanced to place the terminalscrew within the terminal screw-receiving slot permitting the tines onlyto return to their initial position and barring removal of the terminalfrom the terminal screw by the position of the nibs in the path of theterminal screw.
 2. A terminal as defined in claim 1 having an insulationjacket placed about said tubular portion.